Cardiac rhythm management devices can include implantable devices that provide electrical stimulation to selected chambers of the heart in order to treat disorders of cardiac rhythm. For example, an implantable pacemaker can deliver timed pacing pulses to the heart to treat bradyarrhythmia, in which the heart rate can be too slow. In another example of a cardiac rhythm management device, an implantable cardioversion/defibrillator can deliver antitachyarrhythmia pacing (ATP) or a cardioversion or defibrillation shock to treat tachyarrhythmia, in which the heart rate can be too fast, and can also include bradyarrhythmia pacing capability. In yet another example, implantable cardiac resynchronization therapy (CRT) devices can deliver pacing-level pulses to spatially coordinate the heart contraction (with or without altering heart rate) for obtaining a more efficient contraction to improve cardiac output, and such capability can be combined with pacers, cardioverters, or defibrillators. In an even further example, implantable neurostimulation devices can be used to deliver electrical energy to a desired portion of the autonomic nervous system, such as to stimulate or inhibit one of the sympathetic or parasympathetic nervous systems to adjust an autonomic balance to impact cardiovascular performance.